As I am building the London 1832 London street directory at present, I am regularly finding Coffee Houses listed.
Occasionally these are listed on the major pub history site I run, but often NOT.
The beauty of a blog, once you can remember how to login, is that a quick update on a posting is very quick. It also appears that the major search engines like a blog rather than an antiquated web site, so there are many reasons for having a blog on this subject.
A listing of coffee houses would be the next sensible thing to do, and these will be added over the next couple of days. I have yet to decide which year, but maybe the 1836 Pigots directory of Taverns and Coffee Houses would be good. I can then start to add links to these where they later become pubs, or other detail as I see appropriate.